https://www.cnet.com/news/your-google-account-sign-in-gets-material-design-refresh-june-14/

Back in 2014, Google announced Material Design, a visual language to help bridge its Web and Android user interfaces. Google has been updating its G Suite apps since then, such as the new Gmail unveiled in April, and is now changing up a small, but crucial tool you use all the time: The Google sign-in page. 

As of June 14, you'll notice a new Google logo, an outline around the text field and center alignment of all items on the screen, Google said in a post on the G Suite blog.